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4 to throw said valves.

UNITED STATES PATENT OFFICE.

ANDREW' V. SMITH, OF WASHINGTON, DISTRICT OF COLUMBIA.

STEAM-ACTUATED VALVE.

SPECIFICATION forming part of Letters Patent No. 242,231, dated May 31, 1881.

'A Application ined April i9, iesi. (No model.)

To all whom it may concern Beit known that I, A. V. SMITH, a citizen of the United States, residing at Washington, District of Columbia, have invented certain new and useful Improvements in Steam-Actuated Valves; and I do hereby declare the Afollowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being` had to the accompanying` drawings, and to letters or lignres of reference marked thereon, which form a part 0f this specification.

My invention relates to improvements in those valves usually called steam actuated 7' valves 5 and the object is to produce a valve that is thoroughly balanced in its operation, not liable to the wear and friction of ordinary piston-valves, and is yet much simpler in construction; and the invention consists of a hollow piston-valve having a piston-head at each end, secured to a rod or stem, over which a supplementary piston or cut-off valve is arranged, which is operated by an arm secured on a transverse shaft that receives its motion from the cross-head, ordinary piston-rod, or other moving part of a steam-engine. The steam enters into the central part of the steam-chest, and from thence it is admitted to and exhausted alternately through supplementary ports to a chamber at each end of the chest, and throws the valve from one side to the other. The collars on the rod are so placed that the middle or supplementary valve will strike them and give the end piston-valves a positive motion sufficient to open the ports even if the steam fails Suitable lports admit and exhaust the steam from the cylinder, as hereinafter described.

It' also consists in the construction and arrangement of other parts, as will be more fully described hereinafter, reference being had to the accompanying drawings, and the letters of reference marked thereon.

In the accompanying drawings, Figure I is a longitudinal section of my improved valve. Figs. II and III are similar views of modifications of the saine.

In the drawings, A represents the steam'- chest, secured to a cylinder, B, in which is shown a piston, O, of ordinary construction.

In the chest is arranged the valve, consisting of a piston-head, D and D', secured to a rod or stem, E, which is provided at each end with conicaljoints a b and collars or nuts c d that hold the heads in position. The steam is admitted to the central part ot' the chest by al1 opening, F, and passes alternately to a chamber, G H, at each end of the chest, through supplementary ports t' i', and throws the valve 6o from one side to the other. The steam passes then through the openings k L' iu the heads D D', and through the main steam-ports 1J p into the cylinder B. An annular space, c e', is

formed in the heads,through which the steam is exhausted into the exhaust-ports I K and out through an ordinary exhanst-openin g into the atmosphere or condenser.

Between heads D D' is arranged the supplementary valve L, provided with a central 7o opening, l, so as to freely move over the rod E, and a space, m, is formed in said valve, in which the end of an arm, M, oscillates and alternately strikes one end or the other of the valve L, and thus shifts it. This arm receives its motion from the cross-head, piston-rod, or other moving part 0f the engine by any suitable mechanism. The collars d d on the rod E are so placed that the supplementary valve will strike them and give the heads D D' a 8o positive motion sufficient to open the ports i i' if the steam should fail to throw the said heads. The steam in this instance (as shown by the arrows in Fig. I) enters the openin g F and passes to the right-hand side of the cylin- 8 5 der through the opening l of valve L, opening k' in head D', and through the steam-port p' into the cylinder, while at the same time the steam is exhausted from the other end of the cylinder through the opening k in head D and 9o throws the head D in its opposite direction,

and the reverse operation takes place.

In the modication shown in Fig. II theparts are all of a similar construction excepting that the exhaust-ports e e' in the heads D D' are not annular, but merely form pockets e" 6"'. roo

In this instance it is therefore necessary to make one or more openings, o, in the top of the heads D D to balance the area of the exhaust.

In the modification shown in Fig. III the exhaust-ports I K are arranged outside of. the main steam-ports p p', and no steam-openings k 7e are formed in the piston-heads, as the main steam-ports p p communicate with the space formed between the piston-heads. The arm M does not work in the exhaust-openings as in the first cases, but merely in an open space formed between the main steam-ports. The supplementary ports are also one shown at the upper and the other at the lower side of the steam-chest; but this is optional.

Instead ot' the arm `M, a rack and segment, or any equivalent thereof, may be employed to operate the su pplementary valve.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. A steam-actuated bala-need valve consisting of two piston-heads secured to a rod, and a loose supplementary piston-valve arranged between them, to be operated by an arm receiving motion from a moving part of the engine, substantially as shown and specified.

2. A balanced valve consisting ot' two piston-heads secured to a rod and provided with inlet and outlet openings, in combination with supplementary ports, and a loose supplementary piston-valve operated by an arm receiving motion from a cross-head or any other moving part of the engine, substantially as specified.

3, In a steam-actuated valve, the combination ot' two piston-heads secured to a rod, provided with collars, with a supplementary valve impartin g positive motion to the piston-heads, and arranged to be shifted by mechanism operated by a moving part of the engine, substantially as and for the purpose set forth.

4. In a steam-actuated valve, the combination of two piston-heads secured to a rod, and a supplementary piston-valve free to move on said rod, and to be operated positively with a steam-inlet and supplementary ports leading to chambers at each end of said steam-chest, substantially as and for the purpose herein speciiied.

5. The combination of two piston-heads, D D', having inlet and outlet ports, and secured to a rod, E, with a loose supplementary valve, L, operated positively by an arm, M, or its equivalent, and the supplementary ports it" and chambers G H, all substantially as shown and specified.

6. The combination of the two piston-heads D D', having pockets e 0'", and secured to a rod, E, with the supplementary valve L, operated by an arni, the steam -chest A, supplementary ports t' i', and exhaust-ports I K, all arranged substantially as shown and specified.

In testimony whereof I affix my signature in presence of two witnesses.

ANDREW vfsMrrH.

Witnesses:

C. R. ROELKER, Gr. IV. BAiRD. 

